US4494137A - Integrated interface circuit between the RGB matrix and the video output stages of color-television sets - Google Patents

Integrated interface circuit between the RGB matrix and the video output stages of color-television sets Download PDF

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Publication number
US4494137A
US4494137A US06/388,824 US38882482A US4494137A US 4494137 A US4494137 A US 4494137A US 38882482 A US38882482 A US 38882482A US 4494137 A US4494137 A US 4494137A
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digital
analog
input
signal
rgb matrix
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US06/388,824
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English (en)
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Laurin C. Freyberger
Bernd Novotny
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ITT Inc
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ITT Industries Inc
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Assigned to ITT INDUSTRIES INC 320 PARK AVE NEW YORK N Y 10022 A CORP OF DE reassignment ITT INDUSTRIES INC 320 PARK AVE NEW YORK N Y 10022 A CORP OF DE ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: FREYBERGER, LAURIN C., NOVOTNY, BERND
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/64—Circuits for processing colour signals
    • H04N9/641—Multi-purpose receivers, e.g. for auxiliary information

Definitions

  • the present invention relates to an integrated interface circuit comprising an operational amplifier between the output of each output amplifier of the RGB matrix and the input of each video output stage driving the picture tube of a color-television set, and subcircuits for brightness adjustment, blanking, external-signal gating, white-level adjustment, and blanking-voltage adjustment, as set forth in the preamble of claim 1.
  • Such interface circuits are disclosed, for example, in the printed publication "Valvo-Entwicklungsmitannonen", No. 77, December 1979 ("Vollst/andiger PAL-Decoder mit der candiden Druckung TDA 3560"), particularly on pages 8 to 12 and 18 to 20.
  • the external signal is gated via a capacitor, so that the DC level of the gated signals must be recovered by clamping it to the black level of the signals provided by the RGB matrix, see FIG. 9 and text on page 11.
  • the brightness adjustment is performed in the prior art arrangement by means of a potentiometer as usual, but this potentiometer drives a special operational amplifier whose gated output acts on the input of the operational amplifier between the output of the RGB matrix and the input of the output stage.
  • the latter operational amplifier has a stable gain, and its output drives the video output stages via a limiter stage followed by an output stage. As shown in FIG.
  • the blanking-voltage and white-level adjustments are effected at the input of the video output stages by means of two trimmer potentiometers one of which is connected in parallel with the base-emitter circuit of the low-end transistor, while the other is inserted between the output of the aforementioned output stage and the input of this transistor.
  • the invention as characterized in the claims is intended to remedy this drawback; it therefore solves the problem of how to simplify an interface circuit of the above kind in such a way that the requirements placed on the operation of this circuit are met with a smaller amount of circuitry; in addition, blanking-voltage adjustment and white-level adjustment, in particular, are to be possible without interaction.
  • the RGB matrix M has one output amplifier for each chrominance channel, i.e., the three output amplifiers MR, MG, MB, where R, G, and B specify the chromaticity being processed, i.e., "red”, “green”, and “blue”, respectively; the same applies to the other subcircuits described below.
  • the output amplifiers MR, MG, MB are chosen to have a low output resistance, which can be achieved, for example, by providing them with emitter-follower or source-follower output stages.
  • each of the output amplifiers MR, MG, MB is connected via a low-value resistor RR, RG, RB to the non-inverting input of an operational amplifier OR, OG, OB, whose output is connected directly to the input of a video output stage VR, VG, VB having its output coupled to the cathode of the color-picture tube CRT.
  • a preferably digitally adjustable resistance network WR, WG, WB providing negative feedback is connected between the output and the inverting input of each of the operational amplifiers OR, OG, OB.
  • the inverting inputs of the operational amplifiers OR, OG, OB are also fed with blanking-voltage control currents IDR, IDG, IDB. In the figure of the drawing, these control currents are provided by digital-to-analog-current converters DR, DG, DB, which convert digital signals into the control currents.
  • the white-level adjustment and the blanking-voltage adjustment can be made independently of each other, because they do not interact.
  • brightness control currents IHR, IHG, INB are applied to the noninverting inputs of the operational amplifiers OR, OG, OB, i.e., to the junctions of the low-value resistors RR, RG, RB and the respective non-inverting inputs.
  • external-signal currents IER, IEG, IEB are supplied to the non-inverting inputs of the operational amplifiers OR, OG, OB.
  • the total currents IR, IG, IB flow through the respective low-value resistor RR, RG, RB and the low-value output resistor of the respective matrix output amplifier MR, MG, MB.
  • this current sum of the respective R-, G-, and B-channel is taken by the blanking circuit BR, BG, BB during the blanking interval, so that the operational amplifiers OR, OG, OB receive no input signal and provide the blanking voltage set by the blanking-voltage adjustment.
  • the RGB matrix M is controlled by digital-to-analog converters AB, AR, AY, which convert digital B-Y, R-Y, and Y signals into corresponding analog signals. These digital signals also occur during digital signal processing; see the above-mentioned DE 28 54 236 A1. They are the digital Blue-minus-Luminance color-difference signal (B-Y), the digital Red-minus-Luminance color-difference signal (R-Y), and the digital luminance signal (Y).
  • B-Y digital Blue-minus-Luminance color-difference signal
  • R-Y digital Red-minus-Luminance color-difference signal
  • Y digital luminance signal
  • the RGB matrix M must be controlled with the usual analog signals, and the control current must be derived, in the known manner, from the respective analog signals by means of voltage-to-current converter stages.
  • the invention is thus applicable both to color-television receivers using digital signal processing and to receivers using analog signal processing.
  • the individual subcircuits of the integrated circuits are commonly implemented with insulated-gate field-effect transistors, i.e., in MOS technology.
  • the invention can preferably be implemented in 3D bipolar technology, i.e., in triple diffused technology, particularly if analog signal processing is used in the television receiver.

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  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Processing Of Color Television Signals (AREA)
  • Video Image Reproduction Devices For Color Tv Systems (AREA)
US06/388,824 1981-07-08 1982-06-16 Integrated interface circuit between the RGB matrix and the video output stages of color-television sets Expired - Fee Related US4494137A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP81105292 1981-07-08
EP81105292A EP0069166B1 (de) 1981-07-08 1981-07-08 Integrierte Interfaceschaltung zwischen der RGB-Matrix und den Video-Endstufen von Farbfernsehgeräten

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US4494137A true US4494137A (en) 1985-01-15

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US06/388,824 Expired - Fee Related US4494137A (en) 1981-07-08 1982-06-16 Integrated interface circuit between the RGB matrix and the video output stages of color-television sets

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US (1) US4494137A (enrdf_load_html_response)
EP (1) EP0069166B1 (enrdf_load_html_response)
JP (1) JPS5869192A (enrdf_load_html_response)
DE (1) DE3169370D1 (enrdf_load_html_response)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4722005A (en) * 1986-09-12 1988-01-26 Intel Corporation Software controllable hardware CRT dimmer
US5218433A (en) * 1988-07-08 1993-06-08 Commonwealth Scientific And Industrial Research Organisation Real time scanning device signal processing circuit including color signal and blanking signal generating circuits
US5463288A (en) * 1993-09-03 1995-10-31 Thomson Consumer Electronics, Inc. Bus controlled electrode voltage for a cathode ray tube
US20030001976A1 (en) * 2001-07-02 2003-01-02 Matsushita Electric Industial Co., Ltd. Pedestal level control circuit and method for controlling pedestal level

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3611736A1 (de) * 1985-04-12 1986-10-23 Hazeltine Corp., Commack, N.Y. Farbvideomonitor

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3701843A (en) * 1970-10-05 1972-10-31 Zenith Radio Corp Matrix amplifier network with novel d-c set-up arrangement
US4167751A (en) * 1978-06-12 1979-09-11 National Semiconductor Corporation Current matrix for encoding television video signals
US4270139A (en) * 1978-12-15 1981-05-26 Itt Industries, Inc. Color television receiver comprising at least one integrated circuit for the luminance signal and the chrominance signals
DE2947212A1 (de) * 1979-11-23 1981-05-27 Loewe Opta Gmbh, 8640 Kronach Farbsignalsverarbeitungsschaltung in integrierter schaltungstechnik fuer ein farbfernsehempfangsgeraet
US4347528A (en) * 1981-03-16 1982-08-31 Zenith Radio Corporation G2 Set-up circuit for a television receiver

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3701843A (en) * 1970-10-05 1972-10-31 Zenith Radio Corp Matrix amplifier network with novel d-c set-up arrangement
US4167751A (en) * 1978-06-12 1979-09-11 National Semiconductor Corporation Current matrix for encoding television video signals
US4270139A (en) * 1978-12-15 1981-05-26 Itt Industries, Inc. Color television receiver comprising at least one integrated circuit for the luminance signal and the chrominance signals
DE2947212A1 (de) * 1979-11-23 1981-05-27 Loewe Opta Gmbh, 8640 Kronach Farbsignalsverarbeitungsschaltung in integrierter schaltungstechnik fuer ein farbfernsehempfangsgeraet
US4347528A (en) * 1981-03-16 1982-08-31 Zenith Radio Corporation G2 Set-up circuit for a television receiver

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
Vollst ndiger Pal Decoder Mit Der Integrierten Schaltung TDA 3560 Dec. 1979, Valvo Entwicklungsmitteilungen. *
Vollstandiger Pal-Decoder Mit Der Integrierten Schaltung TDA 3560 Dec. 1979, Valvo-Entwicklungsmitteilungen.

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4722005A (en) * 1986-09-12 1988-01-26 Intel Corporation Software controllable hardware CRT dimmer
US5218433A (en) * 1988-07-08 1993-06-08 Commonwealth Scientific And Industrial Research Organisation Real time scanning device signal processing circuit including color signal and blanking signal generating circuits
US5463288A (en) * 1993-09-03 1995-10-31 Thomson Consumer Electronics, Inc. Bus controlled electrode voltage for a cathode ray tube
US20030001976A1 (en) * 2001-07-02 2003-01-02 Matsushita Electric Industial Co., Ltd. Pedestal level control circuit and method for controlling pedestal level
US7030936B2 (en) 2001-07-02 2006-04-18 Matsushita Electric Industrial Co., Ltd. Pedestal level control circuit and method for controlling pedestal level

Also Published As

Publication number Publication date
EP0069166B1 (de) 1985-03-20
JPS5869192A (ja) 1983-04-25
DE3169370D1 (en) 1985-04-25
JPH0245877B2 (enrdf_load_html_response) 1990-10-12
EP0069166A1 (de) 1983-01-12

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